Add aggregation for publication_information

This is the aggregation only. Adding the filter will come next.

Author: matt-bernhardt

app/graphql/types/aggregations_type.rb

@@ -12,6 +12,7 @@ class AggregationsType < Types::BaseObject
     field :languages, [Types::AggregationCountType], null: true, description: 'Total search results by language'
     field :literary_form, [Types::AggregationCountType], null: true,
                                                          description: 'Total search results by fiction or nonfiction'
+    field :publication_information, [Types::AggregationCountType], null: true, description: 'Total search results by publisher'
     field :source, [Types::AggregationCountType], null: true,
                                                   description: 'Total search results by source record system'
     field :subjects, [Types::AggregationCountType], null: true, description: 'Total search results by subject term'

app/graphql/types/query_type.rb

@@ -152,6 +152,7 @@ def collapse_buckets(es_aggs)
         subjects: es_aggs['subjects']['subject_names']['buckets'],
         languages: es_aggs['languages']['buckets'],
         literary_form: es_aggs['literary_form']['buckets'],
+        publication_information: es_aggs['publication_information']['buckets'],
         format: es_aggs['content_format']['buckets'],
         content_type: es_aggs['content_type']['buckets']
       }

app/models/opensearch.rb

@@ -240,6 +240,11 @@ def aggregations
           field: 'literary_form'
         }
       },
+      publication_information: {
+        terms: {
+          field: 'publication_information'
+        }
+      },
       source: {
         terms: {
           field: 'source'